When a patient's knee is severely damaged, such as by osteoarthritis, rheumatoid arthritis, or post-traumatic arthritis, it may be desirous to repair and/or replace portions or the entirety of the knee with a total or partial knee replacement implant. Knee replacement surgery, also known as total knee arthroplasty (TKA), can help relieve pain and restore function in injured and/or severely diseased knee joints, and is a well-tolerated and highly successful procedure. Where a total joint replacement is needed, it is often performed by a surgeon via an open procedure, although various less-invasive and/or minimally-invasive approaches have been proposed and developed as well.
In a typical TKA procedure, once the underlying bony anatomical support structures have been prepared, both the tibia and femur can receive an artificial joint component made of metal alloys, high-grade plastics and/or polymers to replace native anatomy and desirably function as a new knee joint. In the case of tibial implant components, the artificial joint can include a metal receiver tray that is firmly fixed to the tibia. In many cases, the tibial implant further includes a medical grade plastic insert (which may also be referred to as a “spacer”) that can be attached to the tray and positioned between the femoral component(s) and the tibial tray to create a smooth gliding surface for articulation of the components. Such a system can also allow for inserts of multiple sizes and/or thicknesses, which facilitates in-situ balancing of the knee as well as allowing the placement of inserts of differing designs and/or shapes.
While the implantation of TKA components via surgical procedures is a well accepted procedure that is well tolerated by patients and has a high success rate, standard TKA procedures typically focus on axial and rotational alignment of the prosthesis components and ligament balancing. Even though TKA has been constantly improved, e.g., by introducing navigation techniques, TKA patients often experience poorer functional outcomes than total hip arthroplasty patients, which suggests that additional design factors might warrant consideration.